From 65a4aaeca350135f479f3bc435b61abeba313f9c Mon Sep 17 00:00:00 2001
From: Adam Jeniski <adam.jeniski@flashtalking.com>
Date: Thu, 14 Dec 2023 20:29:55 -0500
Subject: [PATCH] fix memoization

---
 2023/src/day12.clj | 74 ++++++++++++++++++++++++----------------------
 1 file changed, 39 insertions(+), 35 deletions(-)

diff --git a/2023/src/day12.clj b/2023/src/day12.clj
index 51a4dc8..0b8f4cb 100644
--- a/2023/src/day12.clj
+++ b/2023/src/day12.clj
@@ -7,53 +7,57 @@
                             (update 1 #(->> (str/split % #",")
                                             (mapv parse-long)))))
 
-(defn make-anso []
-  (with-local-vars
-   [ans (memoize
-         (fn f [dots blocks i bi current]
-           (let [len-blocks (count blocks)
-                 dot_i (when (< i (count dots)) (get dots i))]
-             (if (= i (count dots))
-               (cond (and (= bi len-blocks)
-                          (= current 0))
-                     1
-                     (and (= bi (dec len-blocks))
-                          (= current (get blocks bi)))
-                     1
-                     :else
-                     0)
-               (->> [\. \#]
-                    (map #(if (or (= dot_i %)
-                                  (= dot_i \?))
-                            (cond (and (= % \.)
-                                       (= current 0))
-                                  (f dots blocks (inc i) bi 0)
+(defn ans [dots blocks]
+  (let [dp (atom {})
+        f
+        (fn f [dots blocks i bi current]
+          (or (@dp [i bi current])
+              (let [len-blocks (count blocks)
+                    dot_i (when (< i (count dots)) (get dots i))
+                    v (if (= i (count dots))
+                        (cond (and (= bi len-blocks)
+                                   (= current 0))
+                              1
+                              (and (= bi (dec len-blocks))
+                                   (= current (get blocks bi)))
+                              1
+                              :else
+                              0)
+                        (->> [\. \#]
+                             (map #(if (or (= dot_i %)
+                                           (= dot_i \?))
+                                     (cond (and (= % \.)
+                                                (= current 0))
+                                           (f dots blocks (inc i) bi 0)
 
-                                  (and (= % \.)
-                                       (> current 0)
-                                       (< bi len-blocks)
-                                       (= (get blocks bi) current))
-                                  (f dots blocks (inc i) (inc bi) 0)
+                                           (and (= % \.)
+                                                (> current 0)
+                                                (< bi len-blocks)
+                                                (= (get blocks bi) current))
+                                           (f dots blocks (inc i) (inc bi) 0)
 
-                                  (= % \#)
-                                  (f dots blocks (inc i) bi (inc current))
+                                           (= % \#)
+                                           (f dots blocks (inc i) bi (inc current))
 
-                                  :else 0)
-                            0))
-                    (reduce +))))))]
-    (.bindRoot ans @ans)
-    @ans))
+                                           :else 0)
+                                     0))
+                             (reduce +)))]
+                (swap! dp assoc [i bi current] v)
+                v)))]
+    (f dots blocks 0 0 0)))
 
+;; part 1
 (->> (get-puzzle-input 12)
      (map parse-line)
-     (map #((make-anso) (first %) (second %) 0 0 0))
+     (map #(ans (first %) (second %)))
      (reduce +))
 
+;; part 2
 (->> (get-puzzle-input 12)
      (map parse-line)
      (mapv (fn [[s cnts]]
              [(str/join (interpose "?" (repeat 5 s)))
               (vec (apply concat (repeat 5 cnts)))]))
-     (pmap #((make-anso) (first %) (second %) 0 0 0))
+     (pmap #(ans (first %) (second %)))
      (reduce +))